San Francisco is 6.1% Black
Would maybe slow the roll on who is more diverse.
SF is more diverse (even just racially; ethnicity and national origin just makes that even more clear.) There's more to the world that White and Black.
(Also, in the Bay Area, Oakland is 22.7% Black and about the population of Tulsa, so if you are looking for concentrated Blackness, the Bay Area has Tulsa beat on that as well as diversity.)
As for Oakland the black pop is steadily declining, and might even be sub 20% when 2020 Census #s are released, in a decade might be mid teens.
No, in the context of the posts upthread of it, while it referenced an anti-black mass slaughter as an indicator of unwelcoming aspects of local culture, it did not imply that it was just talking about blacks.